Melling Oil Pump Upgrade Guide for LS

The factory LS oil pump suffers from cavitation above 6,200 RPM, which results in a drop in oil flow of nearly 1 GPM by 7,000 RPM, as well as introduce aeration into the oil. This can lead to oiling related issues throughout the engine. Upgrading the oil pump is recommended any time there is cause to remove the front timing cover in order to improve oiling. This is especially important when adding power and rpm to a given combination.

Note that several different late model GM vehicles contain a secondary oil pressure relief valve in the oil pan. This is used to accommodate the OEM high volume oil pump and the large swings in oil demands for engines equipped with VVT and AFM. This relief begins to open at about 55psi of oil pressure, and can limit oil pressure seen with a higher pressure aftermarket pump. This relief can be eliminated with the oil pan removed from the vehicle by removing it and installing a M14x1.5. This is not required when upgrading the oil pump, and the benefits of an aftermarket pump can still be appreciated without removing the secondary pressure relief. Extreme RPM and horsepower applications should consider this modification to maximize oil pressure. We do not recommend removing this bypass for engines using the 10355 oil pump unless combined with additional bearing clearance.

Melling 10295

Stock volume, high pressure. OEM (LS3) 6.8gpm volume, +10psi pressure.

This is an acceptable replacement for the OEM LS3 oil pump in stock and mild to moderate naturally aspirated applications with no additional oil system demands (larger cooler, increased bearing clearance, turbo, etc). This pump is not suitable for VVT applications.

  • Red spring (installed) – 70psi bypass
  • Optional Blue spring – 60 psi bypass
  • Optional Silver “COPO” spring – 85psi bypass

Melling 10296

High volume, high pressure. 8gpm volume, +10psi pressure. Requires 6+ quart oil sump capacity.

We recommend this pump as our “go-to” upgrade for the OEM LS3 oil pump in naturally aspirated and power adder applications. This pump can provide some added oil volume for added oiling system demands such as external coolers, larger bearing clearances, turbocharger, etc. The added volume is also a benefit in maintaining solid oiling with significantly increased RPM. This pump is not suitable for VVT applications.

  • Red spring (installed) – 70psi bypass
  • Optional Blue spring – 60 psi bypass
  • Optional Silver “COPO” spring – 85psi bypass

Melling 10355

High volume, high pressure. 9.5gpm volume, +10psi pressure. Suitable for VVT and AFM. Requires 6+ quart oil sump capacity.

We recommend this pump as an upgrade for the OEM LS3 oil pump in applications with added oiling system demands such as large external oil coolers, larger bearing clearances, turbochargers, etc. This is also the recommended oil pump for extreme (8000+) rpm applications. We recommend this pump as a replacement for the OEM L99 oil pump in all VVT applications.

  • Orange spring (installed) – 70psi bypass
  • Optional Yellow spring – 60 psi bypass
  • Optional Green spring – 80psi bypass

Questions?

We recognize these are general suggestions.  Want to know what we recommend for your specific build?  Just press that “Questions? Ask Us?” button in the bottom right hand corner, and we will get back with you ASAP!

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2 thoughts on “Melling Oil Pump Upgrade Guide for LS

  1. Zack M says:

    My ls3 is throwing a P0523 dtc, was wondering if I’m starving the engine of oil. Don’t know if you’ve experienced a car do this before and was wondering your opinion on what it could be. Thanks

    • Andrew Cammer says:

      More often than not this will likely be a sensor issue, although an oil pump failure is not unheard of. I would validate oil pressure with a mechanical gauge – if it’s present then likely just needs a sensor. If the pump is indeed bad, then you’ll need to replace that, and you’ll want to evaluate if any other engine damage occurred as a result of running without oil pressure.

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